help please

[Mazzon]

This weekend was the second time i ran my car this year. i have an 05 gt. bone stock it ran 14.1 at 102ish mph with a 2.4 60ft.
since then i picked up 65rwhp, 4:10 gears, and mickey thompson drag radials
3 weeks ago i ran the car again ...on a hot humid sticky night. i managed a 13.8 at 104, again with a 2.4 60 ft. this is without the mickey ts (on the horrible 18inch bfgs spinning hard)

this weekend i finally ran the car with the tires. but somethings up
my best was a 14.0 with a 1.7 60ft at 96mph.
the car felt like it had a 100hp loss, first gear was strong but 3rd is where i felt the difference. people suggested changing the spark plugs, which i am doing today.. any other ideas?..

thanks​

 

[Grabber]

Driving is a huge factor.

What RPM are you launching at? Are you slipping the clutch? Doing a healthy burnout? What type of weather conditions are you running in?

Is the car tuned? Have you ever changed the plugs?

There are multiple things that could be wrong.

 

[stang06gt]

Ya your trap speed is way down. How heat soaked was it when you ran? If its tuned did you try reloading your tune?

 

[Brezick]

well with the change to 4.10's trap speed should drop some, but idk about 8mph. With the gear change, are you having to do another shift? What RPM are you crossing the line at?

All things same, dropping .7 in the 60 should at the very least get you in the 12's.

 

[Mazzon]

launching at 6500. launching and hooking hard .. really good 60 fts
seems not to want to rev as fast in 3rd gear. car was not heatsoaked. it sat for about 3 hours when i ran it.. it makes 310hp and 330 at the wheels and a/f ratio is perfect.
im crossing the line at 5500 in 4th gear. i have a video.. but dont mind i missed second gear.

http://www.youtube.com/watch?v=zug4Wpaxkm8

this is my friends car. u can see in my mirror he starts to catch up.. bone stock that didnt happen, its always steadily pull.. i dont know what the issue is

 

[Deez-67]

more seat time.

I'm running less bolt-ons than you and I put down a 12.6 on DR's. without DR's I ran a 13.7

 

[Mazzon]

without drs i ran 13.8 at 102mph on a VERY humid night.
something is holding it back,

 

[Brezick]

well ya, my best run when the humidity was 80%+ high temps was 12.8. I left after two passes

as far as third gear, what RPMs does the car drop to after you shift from 2nd? I stay in third longer than the rest, but the RPMs start at 4800 and slowly rise to 6500.

 

[BruceH]

I'd try a custom tune instead of the canned sct you have now.

 

[Mazzon]

i have a custom dyno tune

 

[psfracer]

I agree there is something wrong---its not driver mod as you lost 8 mph in 3 weeks.

A couple questions--

With the m/ts, what air pressure are you running?
Post up the time slip, or tell me what was your mph at the 1/8th, and compare that to your mph at the 1/4 (96 mph). Post up your split times.

A n/a car in the 12s should have a mph difference of roughly 20-22 mph from the 1/8th to the 1/4. If, for example, your mph at the 1/8th is 82, and the mph at the 1/4 is 96 (only a 14 mph difference) then there is something definitely wrong, and the car is probably pulling timing, you need new plugs, or the converter / clutch is going south.

In any case, post up the incremental numbers so we can see what is happening throughout the run.

 

[Mazzon]

i will post the time slip when i get home.. but i ran 3 times. i lowered it from 16psi (first run), 12psi(2nd), and 10psi 3rd... ironically the 3rd pass i hit a 14.0.. while the other two were 14.2 and 14.1 all with 1.7-1.9 60 fts
it did feel stron first and 2nd gear.. ive made about 40 passes in this car and i know when it is comming time to shift from 3rd into 4th gear,, it felt at least a full second longer. i changed the plugs yesterday and im heading back to the track sunday to see if that fixed the issue

 

[Brezick]

I usually do better with 20-23 PSI when using Drag radials. I have Nitto's so IDK if the same applies to MT DR's.

 

[Sharad]

96mph trap speed in an S197 with bolt ons is a major major problem. Unless your track's elevation is: outer space.

The 1.7 sixty on the mickeys isn't too bad, but that trap speed is trying to tell you something.

 

[Mazzon]

I agree there is something wrong---its not driver mod as you lost 8 mph in 3 weeks.


A couple questions--

With the m/ts, what air pressure are you running?
Post up the time slip, or tell me what was your mph at the 1/8th, and compare that to your mph at the 1/4 (96 mph). Post up your split times.

A n/a car in the 12s should have a mph difference of roughly 20-22 mph from the 1/8th to the 1/4. If, for example, your mph at the 1/8th is 82, and the mph at the 1/4 is 96 (only a 14 mph difference) then there is something definitely wrong, and the car is probably pulling timing, you need new plugs, or the converter / clutch is going south.

In any case, post up the incremental numbers so we can see what is happening throughout the run.

my mph at the 1/8th mile was between 79-81.. if that tells you something

 

[psfracer]

Ok, so 81 mph to 96 mph is 15 mph. That is a sign something is WAY OFF on the big end. Sparks plugs would be a cheap first step. Next would be to datalog your timing and see what is happening on the big end. If the car is not pulling timing, and is at normal operating temperature, I would look at clutch / converter.

 

[fdjizm]

Might be a slipping clutch, if it's stock. those 6500rpm launches will only go so far.

 

[Mazzon]

i got the plugs changed.. the car only has 50 000kms on it..(roughly 28000 miles).this was my first time launching the car at 6500, and my first time on DRs. i believe my clutch is fine. I just had it retuned a few months ago. Heading back to the track soon, hopefully my problems are solved. It does feel like i picked up a few ponys riping it around town. but i dont know for sure. I have the SCT software, so i should learn how to data log it.

Thanks for all your help, i appreciate it

 

[808muscle]

Very weird...1.7 sixty foot and then it falls off. Good luck.

 

[Blackblurr2007]

I had the same problem. These cars run good 1/8 -1/4 mph. 82-85 and should be 106 min.. I had similar hp and the clutch went south after a few launches. You wont see a problem till 3-4th! That hp you have shuld be 12.70@ over 108mph EZ.. Hope that helps! Jim